[Laszlo-user] combo box bloat == 100 meg laszlo app

Benjamin Shine ben at laszlosystems.com
Fri Mar 24 18:43:39 EST 2006

How about using checkboxes or radio buttons instead of comboboxes,  
for yes/no choices? The combobox is a lot of machinery for just  
giving the user a binary choice.


On Mar 24, 2006, at 3:21 PM, William Krick wrote:

> My app has a lot of Yes/No comboboxes.
> Would there be any benefit to making them all datacomboboxes and  
> pointing
> them all at the same dataset containing two items, "yes" and "no"?
> Does changing the selection in one datacombobox, navigate all  
> datacomboboxes
> linked to the same dataset?
> -----Original Message-----
> From: Jim Grandy [mailto:jgrandy at laszlosystems.com]
> Sent: Thursday, March 23, 2006 6:48 PM
> To: William Krick
> Cc: Laszlo-User
> Subject: Re: [Laszlo-user] combo box bloat == 100 meg laszlo app
> datacombobox *is* newcombobox, just under a different name. The
> correspondence is:
> incubator/newcombobox becomes base/basedatacombobox
> incubator/lzcomombobox becomes lz/datacombobox
> The main cause of bloat and slow initialization with combobox is that
> it creates a floatinglist instance when it is initialized. So all of
> the comboboxes in your application will have an associated
> floatinglist instance.
> We improved that in newcombobox to share a floatinglist between all
> newcombobox instances using the same style. But this created bugs
> with data binding and synchronization, so with datacombobox we
> changed it so that each instance has its own floatinglist, but the
> floatinglist is only instantiated when needed.
> This is still a bit fragile because newcombobox/datacombobox is
> engineered to get its selection manager and data state from the
> floatinglist -- selection and value have to be managed manually until
> the floatinglist is created. There are improvements to be made there.
> Note that both newcombobox and datacombobox are entirely data-driven
> (hence the name of the latter), so you can't supply the menu items
> statically as you can with combobox.
> jim
> On Mar 23, 2006, at 1:26 PM, William Krick wrote:
>> I'm working on an OpenLaszlo application that has a lot of controls
>> for data
>> input.
>> When I load our app up in a browser and check the memory use for that
>> browser instance in task manager, it's around 100 megs.
>> Obviously this is WAY too large and something has to be done to
>> bring the
>> size down.
>> After some digging, it appears that the majority of our apps memory
>> use is
>> due to combo boxes.  LOTS of comboboxes.
>> The combobox is critical to our application so we need a solution  
>> that
>> brings the memory use for comboboxes way down.
>> Also, a side effect of this bloat is that anything that dynamically
>> manipulates the contents of a combobox like adding or removing
>> items, or
>> refreshing the list when connected to a dataset, is unusably slow
>> in our
>> application.
>> I know there was some work done on a "newcombobox" but it appears
>> that that
>> might have been abandoned in favor of the "datacombobox" which  
>> doesn't
>> really address the bloat problem.
>> Can anyone tell me what, if anything, can be done to remedy our
>> situation?
>> My co-worker is putting together and will post an example that
>> specifically
>> addresses the performance problems when manipulating comboboxes but
>> I just
>> wanted to query the list about a solution to the larger problem of
>> application bloat due to comboboxes.
>> Is it possible to strip down the combobox and/or textlistitem to
>> make them
>> less memory hungry?
>> ...
>> Krick
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>> Laszlo-user at openlaszlo.org
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benjamin shine
software engineer
ben at laszlosystems.com

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